1. Field of the Invention
The invention relates to lighted keyboards and more particularly to a backlight keyboard having improved characteristics including the provision of the light guide plate under the keycap, the compact arrangement of the support plate, the light guide plates and the light emitting element, the opaque support plate, the limit members being allowed to travel a limited distance, simplified components, simplified assembly steps, lowered keyboard height, decreased light travel path, the travel path of the keycap maintained at a right angle with respect to the bottom of the keyboard, increased light deflected by the light guide plates, and increased light reaching the bottom of the keycap.
2. Description of Related Art
A conventional backlight keyboard or keypad for use with a calculator, computer, or mobile phone includes a light guide plate, a reflective layer, and a shielding layer all assembled as a stacked component. Light emitted by a light source at a lower portion of the keyboard or keypad may pass through the stacked components to reach a bottom of a keycap.
However, the conventional backlight keyboard or keypad has the following disadvantages: The additional provision of the reflective layer to reflect light from the keycap. The additional provision of the scissors-type structures which increases thickness of the keyboard. Each key of the scissor-type structure on the circuit board must have a plurality of openings, so the brightness will leak light from the opening. The light must pass through multi-layers to the bottom of keycap. The light guide plates are sheet type and have the same size as the support plate which may increase the manufacturing cost and complicate the manufacturing processes.
Thus, the need for improvement still exists.